Allow integer contants to have a U suffix. Improve error reporting for missing closi...

Allow integer contants to have a U suffix.  Improve error reporting for missing closing parentheses.

	PR gas/19910
	* config/tc-sparc.c (sparc_ip): Report an error if the expression
	inside a %-macro could not be fully parsed.
	* expr.c (integer_constant): Accept and ignore U suffixes to
	integers.
	(operand): When a missing closing parenthesis is encountered,
	report the character that was found instead.
	* testsuite/gas/mips/tls-ill.l: Update expected error message.
	* testsuite/gas/sparc/pr19910-1.d: New test driver.
	* testsuite/gas/sparc/pr19910-1.s: New test.
	* testsuite/gas/sparc/pr19910-2.l: Expected error output.
	* testsuite/gas/sparc/pr19910-2.s: New test.
	* testsuite/gas/sparc/sparc.exp: Run the new tests.